At least 23 hostages and 32 militants have died since gunmen stormed a gas complex, officials say. Two additional Americans may be among the dead. But other details remain murky.

A man reads a newspaper in a street of Ain Amenas, near the gas plant where… (Anis Belghoul / AP Photo )

CAIRO — It was a bloody ordeal with tick-tock drama and a watching world.

The hostages at a natural gas complex in the Sahara desert faced four harrowing days trapped between two dangers: Islamist militants who forced some of them to wear explosives belts, and the Algerian military, which showed no inclination to negotiate for their release.

After the army carried out its "final assault" Saturday, Algerian officials said that at least 23 hostages and 32 militants had been killed since gunmen startled the world and rallied Al Qaeda-linked extremists by storming the complex before dawn Wednesday.

The nationalities of the hostages were not revealed. Nearly 700 Algerians and 107 foreigners had been freed or had escaped from the gas field in eastern Algeria over the last two days. When the final assault began Saturday, at least 30 foreigners, including an estimated seven Americans, were unaccounted for.

The United States is "still trying to get accurate information" on what happened, Defense Secretary Leon E. Panetta told reporters while traveling in London. The only confirmed American death was that of Frederick Buttaccio, 58, of Katy, Texas.

Many details of the tense, bloody hours at the complex remain murky. Governments whose citizens were hostages, including those of Britain and Japan, complained that the Algerians did not apprise them of what was unfolding. Reports suggest that no foreign capitals were consulted before the army's first raid on Thursday.

"The loss of life as a result of the attacks is appalling and unacceptable," said British Defense Secretary Philip Hammond, who confirmed word from the Algerians that the hostage crisis was over. "We must be clear that it is the terrorists that bear full responsibility for it."

French President Francois Hollande praised Algeria's handling of the crisis.

"When you have people taken hostage in such large numbers by terrorists with such cold determination and ready to kill those hostages — as they did — Algeria has an approach which to me ... is the most appropriate, because there could be no negotiation," he told reporters.

Algerian officials said the heavily armed militants planted mines and threatened to blow up the complex and kill hostages or use them as shields to escape across the desert into Libya. News reports and accounts from freed hostages suggest a number of hostages were killed Thursday when an army helicopter fired on four, or perhaps five, vehicles moving within the compound.

At one point, the militants reportedly offered to trade two captive Americans for two extremist figures jailed in the United States, including Sheik Omar Abdel Rahman, the blind Egyptian cleric convicted in 1995 of plotting to bomb landmarks in New York.

Saturday's army raid killed 11 militants but not before extremists executed their final seven hostages, two of whom may have been Americans. By nightfall, troops had discovered 15 burned bodies and were securing the plant, where hours earlier gunfights had played out amid the natural gas processing plant's silver pipes and prefabricated housing.

"Our determination is stronger than ever to work with allies right around the world to root out and defeat this terrorist scourge and those who encourage it," said British Prime Minister David Cameron.

Other captives unaccounted for included 14 Japanese, five Britons, two Malaysians and six employees of Statoil, a Norwegian firm. Their fates exposed the heightened risk to Algeria's gas and oil fields, and the skilled foreigners who help work them , at a time of growing Islamic extremism radiating across much of North Africa.

The militants were connected to a group known as Al Qaeda in the Islamic Maghreb, which arose from the Algerian civil war in the 1990s. The attackers reportedly included Libyans, Egyptians and at least one commander from Niger. They said their assault on the compound was in retaliation for French airstrikes recently on rebels fighting to forge an Islamic state in neighboring Mali.

A White House official discounted that theory, saying the attack was planned far in advance of the French intervention in Mali. Accounts by freed hostages and statements by Algerian officials indicated that the militants, some of whom wore fatigues and appeared to know their way around the compound, may have been assisted by contacts inside.

The gas complex, in a town called In Amenas, sits on a border rife with militants, traffickers and weapons, many of them looted and flowing in from an unstable Libya. The suspected mastermind of the hostage crisis was Mokhtar Belmokhtar, a one-eyed Al Qaeda recruiter whose nicknames include Mr. Marlboro for his smuggling networks. He was believed to have been aiding the rebels in Mali.